Assigning IP Address Using Option 82 in one Subnet

Adam Moffett adamlists at
Fri Dec 10 18:08:28 UTC 2010

> "Relay agents are NOT required to monitor or modify client-originated 
> DHCP packets addressed to a server unicast address. This includes the 
> DHCP-REQUEST sent when entering the RENEWING state."

> DHCPDISCOVER from XX:XX:XX:68:6b:7f via eth0.2: network XXXXXX-Net: no 
> free leases
> DHCPDISCOVER from XX:XX:XX:68:6b:7f via

In the piece of RFC you're quoting the key word is unicast.  I believe 
it is quite normal behavior for relay agents to leave unicast packets 
between the client and server unmodified. However, I think that you are 
getting the DHCPDISCOVER both as the original broadcast from the client 
and as a unicast from the relay agent.  I don't believe that's normal.  
Or maybe it is normal for other products, but at least the relay agents 
I use here which are Motorola wireless APs are not behaving that way.

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